I am investigating how known changes in the primary structure of a protein affect the kinetic and equilibrium properties of protein folding reactions. Iso-1 and iso-2 cytochrome c's from yeast are the major focus of the work since these two proteins are particularly well suited for primary structure manipulations by genetics and recombinant DNA methods. Fast kinetics, stopped-flow mixing and temperature jumps will be used to determine which of the kinetic processes in folding of the wild-type protein are perturbed by the altered primary structures of mutant proteins. Nuclear magnetic resonance will be used to characterize stable structure in partially folded native and mutant proteins. The hypothesis that some partially folded mutant proteins are stable structural analogues of transient folding intermediates will be investigated.